This invention relates generally to the recovery of the rubber content of manufactured goods, and particularly to methods and apparatuses for reprocessing rubber tires.
Heretofore the rubber content of used vehicle tires has been recovered rather than incinerated or scrapped. This has been done by mechanically chopping the tires and grinding them and then separating the rubber and metal with a gravity air classifier or centrifuge. In other cases tires have been frozen, as with nitrogen, and then ground. These recycling processes however have been inefficient and very costly. The present invention provides a new method and apparatus for recovering the rubber content of used vehicle tires that is substantially more efficient and less costly to perform.
In a preferred form of the invention goods comprised of both rubber and heavier than rubber material are processed to recover their rubber content. The method comprises the steps of immersing the goods in a bath of liquid having a density greater than the density of the rubber and in which the heavier than rubber is insoluble and has a greater density than the bath. The bath is at a temperature elevated above the melting point of the rubber. This causes the rubber to become molten, to separate from the non rubber material, and rise to the top of the bath. The molten rubber and the heavier materials are then removed from the bath separately.
In another form of the invention apparatus for use in recovering the rubber content of goods that comprise rubber and heavier than rubber material comprises a separation tank, means for heating the separation tank, and a process tube that extends into and out of the separation tank. The process tube has perforations in its mid-portion that are located within the separation tank. The apparatus also has means for pushing the goods in the process tube to the mid-portion where their rubber content may be melted and flow out of the tube through the tube perforations and for pushing the residual non molten content of the goods out of an end of the tube located beyond the perforations.